LD泵浦的1.3at.%Er^(3+):CaF_(2)中红外高功率固体激光器(特邀)  

LD pumped high-power mid-infrared solid state lasers based on 1.3at.%Er^(3+):CaF_(2) crystal(Invited)

作　　者：宗梦雨 张振 刘晶晶 刘杰[1] 苏良碧[2] Zong Mengyu;Zhang Zhen;Liu Jingjing;Liu Jie;Su Liangbi(Shandong Provincial Engineering and Technical Center of Light Manipulations&Shandong Provincial,Key Laboratory of Optics and Photonic Device,School of Physics and Electronics,Shandong Normal University,Jinan 250358,China;Shanghai Institute of Ceramics,Chinese Academy of Sciences,Shanghai 201899,China)

机构地区：[1]山东师范大学物理与电子科学学院山东省光场调控及应用中心山东省光学与光子器件技术重点实验室,山东济南250358 [2]中国科学院上海硅酸盐研究所,上海201899

出　　处：《红外与激光工程》2021年第8期115-120,共6页Infrared and Laser Engineering

基　　金：国家自然科学基金(11974220,61635012,61925508)。

摘　　要：3μm波段激光是高精度外科手术的理想光源,也可作为长波中红外光参量振荡器的有效泵浦源。LD直接泵浦Er^(3+)掺杂晶体是获得2.7~3μm波段中红外激光的有效技术途径,具有成本低、结构紧凑简单等优点。由于Er^(3+)2.8μm激光下能级阻塞问题,一般需要高浓度掺杂,但高浓度掺杂易引起强烈的光吸收,增强了激光晶体的热效应,从而阻碍了激光功率的提升。低声子能量的氟化钙晶体特有的萤石型结构使得三价稀土离子极易形成"团簇",将低浓度Er^(3+)掺杂到氟化钙晶体中即可获得高效率的中红外激光增益介质。笔者课题组使用温度梯度法成功生长了低浓度掺杂1.3at.%Er^(3+):CaF_(2)激光晶体,利用LD直接泵浦获得了2.2 W的中红外激光输出,这是目前利用LD端面泵浦同类晶体中的最高中红外激光输出功率。同时,文中还对上转换泵浦方式下该晶体的2.8μm激光特性进行了研究。实验结果表明,低浓度掺杂的1.3at.%Er^(3+):CaF_(2)晶体是一类具有产业化前景的中红外激光材料,有望推动长波中红外激光器向着结构紧凑、成本低的方向发展。3 μm wavelength laser is an ideal laser source for high precision laser surgery, and can be an effective pump source for mid-infrared optical parametric oscillations. The mid-infrared laser in 2.7-3 μm band can be obtained by laser diode(LD) directly pumping Er^(3+)-doped crystal, which has advantages of low cost, compact and simple structure. The Er^(3+)doping concentration is generally high to solve the laser self-termination. However, high concentration causes strong light absorption and up-conversion, which could enhance the thermal effect of laser crystal and hinder the improvement of laser output power. The characteristic fluorite structure of low phonon energy CaF_(2) crystals makes trivalent rare earth ions easily form "clusters". A laser gain medium with high thermal conductivity can be obtained by lightly doping Er^(3+) into the CaF_(2) crystal. In this work, high quality 1.3 at.%Er^(3+):CaF_(2) laser crystals were successfully grown by temperature gradient method, diode pumped continuous-wave Er^(3+): CaF_(2) laser with maximum output power of 2.2 W was achieved, this is the highest output power in the LD end pumped lightly doping crystals. Furthermore, we demonstrated the 2.8 μm laser continuous-wave performance pumped by 1 532 nm LD. The research of the LD direct pumped high power laser is expected to promote the development of the long-wavelength mid-infrared laser towards the direction of compact structure and low cost.

关 键 词：中红外固体激光 Er^(3+)低浓度掺杂CaF_(2)晶体 高功率激光 LD泵浦 上转换泵浦 

分 类 号：O432.12[机械工程—光学工程]